Why is material rendering transparent?
This has happened to at least 3 times but seems like I don't remember it at all!
it took me a little while to figure it out.
The issue with the teddy bear is that, You have not enabled show emitter in the particle's section.
Hence the render shows just the hairs but not the bear which is emitting those hair particles!

As per the ice flakes I see a collection called sprinkles in particle selection but it seems to be deleted.
the name in the particles seems like just the cached name!